Secondary battery.



UNITED STATES PATENT OFFICE.

WILLIAM MORRISON, OF CHICAGO, ILLINOIS, ASSIGNOR TO KING UPTON, OFCHICAGO, ILLINOIS.

SECONDARY BATTERY.

SPECIFICATION forming part of Letters Patent No. 717,107, dated December30, 1902.

Application filed May 19, 1900- Serial No. 17,206. (No model.)

To ail whom it may concern:

Be it known that 1, WILLIAM MORRISON, a citizen of the United States ofAmerica, and a resident of Chicago, Cook county, Illinois, have inventeda certain new and useful Improvement in Secondary Batteries, of whichthe following is a specification.

In a common form of secondary battery the active surface of the negativeplate is a coating of minium or red lead in the form of a paste, whichin the charge becomes a peroxid of lead. In a positive plate the activesurface is a coating of litharge or yellow oxid of lead, which in thecharge becomes a porous spongy lead mass. To form the red lead into apaste, it is usually mixed with dilute sulf uric acid or sulfuricacidulated water. This produces a small quantity of sulfate of lead in asolution, and in drying the sulfate slowly sets into the mass as ithardens. With this construction, however, when the charging is pressedtoo far the lead sulfate is changed to a peroxid or binoxid of lead, thesulfuric acid is expelled, and the bond is relaxed until the peroxidcoating powders and crumbles away.

The object of the present invention is to overcome this difficulty, andthis I have discovered may be accomplished by using hydrofluoric acid inthe battery by mixing it with the lead paste forming the active materialor material to become active. Hydrofluoric acid being stronglyelectropositive, it will unite with the sulfuric-acid of the electrolyteto form a fluorid of lead which resists the destructive effects ofovercharging hereinabove referred to and perpetuates the bond of thepaste, so as to prevent the latter from crumblin g.

The advantage of the improvement in increasing the longevity ofsecondary batteries will thus be apparent.

I claim as my invention- 1. In a storage battery, the combination of asuitable electrolyte, and positive and negative elements immersed insaid electrolyte, one of said elements having a paste containingfiuorin.

2. In a storage battery the combination of a suitable electrolyte, andnegative and positive elements immersed in said electrolyte, one of saidelements having a paste formed by mixing lead oxid with hydrofluoricacid.

3. A paste for storage batteries formed by combining suitableingredients with hydrofluoric acid.

Signed by me at Chicago, Cook county, Illinois, this 17th day of May,1900.

WILLIAM MORRISON.

\Vitnesses:

GHAs. C. BULKLEY, G. H. BAUMGARTNER.

